Two-temperature refrigerating apparatus



E. F. SCHWELLER TWO-TEMPERATURE REFRIGERATING APPARATUS March 16, 1954 5 Sheets-Sheet l Filed April 28, 1951 x x/ N &672.030

E. F. SCHWE LLER TWO-TEMPERATURE REFRIGERATING APPARATUS March 16, 1954 5 Sheets-Sheet 2 Filed April 28, 1951 FIG. 2

;BY INVENTOR. Z %31% March 16, 1954 E. F. SCHWELLER TWO-TEMPERATURE REFRIGERATING APPARATUS 5 Sheets-Sheet 3 Filed April 28, 1951 y ?:9E HVVENTUR.

M /fl W YFIG. 3

March 16, 1954 E. F. SCHWELLER TWO-TMPERATURE REFRIGERATING APPARATUS Filed April 28, 1951 5 Sheets-Sheet 4 FIG.

;8% INVENTOR.

March 16, 1954 E. F. SCHWELLER 2,672,030

TWO-TEMPERATURE REFRIGERATING APPARATUS Filed April 28, 1951 5 sets-sheet 5 F. .MONDAY TUE. WEB. TIIUR. FRI. SAT. SUNDAY 50-- --so rEMP. LINER 38 vvvvvvvvvvvvlvvv vvvvvvvvvvvvvvvvvvVV -I0-- TEMP. FROZEN FOOD COMPT.3

/ IVENTOR.

?Fco W Patented Mar. 16, 1954 TWO-.TEMPERATURE REFKIGERATING APBARATUS Edmund F.1Schwel1er, Daytop, .Ohio aigmr to General M torsorp io t Dayton, O io, .a corpora-ton ofrDelaware Appliatio April 28, 1951, Serial No. 223,'531

This-invention relates 'to refrigerating apparatus.

An=object ofthis invention is to provide animproved mechanical refrigerator which is adapted to "be-'manufactured in iarge quantities and to bedistributed and used throughout the United States. It is providedin its upper portion-with a 'very lowtemperature frozen food compartment of'reotangular cross section adapted to receive reetangular frozen food packageato be fully packed with them, and 'to prevent local warm- The Spots among such frozen food packages. refrigera-tor is aisoprovided With an unfrozen food compartment'to 'be maintained at a low temperatura'above 32 F., 'which compartment is adaptedtoreceive feeds in large quantitie,

which are tobe maintained above 3 2 F., and

Whichare notlikely to-be dehydrated. The refrigerator also is provided with a space within the unfrozen food ompa-rtment irwhich relatively high humidities *are maintainedandin Whih foods-maybepreservedwhich are -li-keiy to otherwise become dehydrated. i

*Notwithstanding these advantages, the refrigerator -is adapted to' operatesatifactorily varying atmospheric temperatures -ranging frombe 1ow -50 F. -to as high as considerab-ly above,

lom-'F: It-isalso adapted to operate sa-tisfatoriiy invarying d'egrees of-atmospheric hunidity; frequently reachirg suhstantiaily the saturation pointof &% relative humidit-m without danger of accumulating undesirablemoisture within the insulation surrounding `'the compartments.

To this'end, the cabiret isprovided With -an outr oasingwhich issubstantially. *hermeticahy sealed thro ehout and isengaged--by the door' construction: in a manner to reduce v the in'ltr mohoi-outside' air into the refrigerator.

The {rozen food compartment is virtuaily surrounded-on-aljl sides,-except' the door side, with afreezing 'evaporator placed 'on theoutside of blocking the =aecess-of moisture'ito the freezing; evaporator 'to such anextent 4 that only 'a 'slight amount of frost can ever 'gather on the .outeras ma.

face of the frozen food compartment (the accumulation of which steps in the early days of operation) and cannot gather at all; inside ..of

the bags.

The unfrozen food compartment. is alsosur rounded by similar bags of'insu'lation pressed against :the outer surface of the -compartment so that no moisture whatever .can gather inside the bags. and substantialiyno r-moistnre can gather on the enter wallsofthe unfrozenfood.

compartment. I'l'enlOWGI' portion 'of the un frozen food compaitment is surrounded gand contaeted :by a refri erant, pamceolng, -.evapo.-

r rator which is in closed circuit reiationshipwith a refrigerant condenser cooled :by .the freezing evaporator surrounding thefrozen food'. com-L- partment. tThisspace, in :the lower partiof the unfrozen food' compartment, is` provided with :one or moreeovered, humidityreta'ming, food re ceiv-ing panst orrdrawers adapted to maintainvY-a space at relatively low temperatureand high humidity for storing of green .vegetables andthe like.

orderato ;cool the major portion of the unlfrozen food compartment, and ir order toupre vent the `aecunculatiem of moisture either inside of &the unfrozen foodcompartment .or. in the in-` sulation space, a 'frosting ;and defrosting...evaporator. is placed-inside :of ;the unfrozen food eompartment and is preferably in the shape of a vertical reetangula-r plate, in the upper real' part of the unfrozen food compartment; This frosting and .defrosting evaporator--may :becooled by placing. it 'in closed refrigerant flow relationship .a .condenser cooled b y-the freezing evaporator surrounding' 'the fr-ozen food *compartment. The oi' ter surface of the frosfiing and defrosting-.evaporator iseolder than the outer .surface .of the :pan cool-ing evaporator and hence .continuanymfreezes moisturerom the insulation spaee and prevents any material aecumulation within it.

A motor compressor unit andcondenser-are placed' in the `lower part of the refrigerator-' ard arein refrigerant' flow relationsl-iip with th-e The compressor is -ey1ed freezing evaporator. 4 freeuentlywat 'least several 'times -aday) tg maintain the desired temperature --conditions in the refrigerator "and this -is aceompl-ished by providing a thermostatic switeh having its--'-ther-' mostatiebulb oloselvadjacent the condenser which is in refrigerantow relationshipwith ;the

i hos n d de rosti vaptq atqf- This-refrigerator is adapted to maintain 'the frozen food compartment uninterruptedly below 32 F. without defrosting for long periods of time, such as several months, by the normal cycling of the motor compressor unit, which Cycling occurs several times an hour. The refrigerator may be easily maintained in proper condition by occasionally and quickly defrosting the frosting and defrosting evaporator, which operation may be performed so quickly that no melting can take place in the frozen food compartment. The refrigerator can operate at very high eificiency in all sections of the country under varying conditions of atmospheric temperature and humidity without becoming frost or moisture bound either within its food preserving compartments or within its insulation space.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Fig. 1 is a vertical sectional view taken substantially along the line l-l of Fig. 3, with the side insulation removed, of the upper portion of a two temperature refrigerator embodying one form of my invention;

Fig. 2 is a vertical sectional view taken substantially along the line 2-2 of Fig. 3, with the side insulation removed, of the bottom portion of the two temperature refrigerator, the upper portion of which is shown in Fig. 1;

Fig. 3 is a fragmnetary front vertical sectional view taken substantially along the line 3-3 of Figs. 1 and 2;

Fig. 4 is a fragmentary rear vertical sectional view taken substantially along the line 4-4 of Figs. 1 and 2, with the back insulation removed;

Fig. 5 is a front sectional View partly diagrammatic taken substantially along the line 5-5 of Figs. 6 and 7 of the freezing compartment and the freezing evaporator;

Fig. 6 is an exploded left side View of the freezing compartment and evaporator shown in Fig. 5 including the two secondary condensers and the accumulator;

Fig. 7 is an exploded right side view of the freezing compartment shown in Fig. 5 with the secondary cooling coils for the high humidity compartment and the frosting and defrosting evaporator plate being added;

Fig. 8 is a bottom view of the freezing compartment shown in Fig. 5;

Fig. 9 is a back View of the freezing compartment and the other two evaporators, and

Fig. 10 is a temperature time chart of the three evaporators in the cabinet.

Referring now to the drawings, there is provided an outer sheet metal cabinet shell enclosing the top 22, bottom 24, sides 28 and 28, and rear 30 of the cabinet which is hermetically sealed. The joints of this shell 20 are sealed by welding or other suitable metal seal and preferably are double sealed on the interior by the use of some form of non-metallic sealing material such as an asphalt applied in molten form.

There is provided a freezng compartment 32 in the upper portion of the cabinet in the form of a box-shaped metal container having it front side open. This compartment container 32 has its front edges connected by a member 34 of a thermoplastic material, called a breaker strip or throat, to the front portion 36 of the outer shell 20 of the refrigerator. Beneath the freezing compartment container 32 there is provided a food compartment 38 in the form of a box-shaped metal container having its front side open. The front edges of this boX-shaped container 38 forming the food compartment are connected by breaker strip or throat i@ of a thermoplastic or other suitable poor heating conduit material With the front wall 36 of the outer shell 20. A separate upper door 42 containing insulation is provided for the freezing compartment 32 and is provided with a seal 44 of a suitable synthetic rubber which extends entirely around the door 42 to make sealing engagement with the front 36 of the outer shell 20 so that when the door 42 is closed the freezing compartment 32 is substantially sealed from outside air. The lower food compar-tment 38 is provided with a separate door 46 containing somewhat less insulation than the door 42. It is likewise provided with a similar seal 48 extending entirely around the door which makes scaling engagement with the front 35 of the outer shell 29. This seals the food compartment'38 from the outside air. The scaling of the doors 42 and 46 against the front side 36 of the outer shell Zt completes the hermetical scaling of the outside of the cabinet so that no air and moisture can enter the cabinet except by opening one of the doors.

The freezing compartment 32 is provided with smooth inner wall surfaces so that any snow or frost accumulating therein can be easily scraped or brushed off. When no melting occurs, such snow and frost will not adhere tightly to the surface of the freezing compartment 32. The freezing compartment 32 is cooled by a primary refrigerating system which includes a sealed motor compressor unit 50 which delivers compressed refrigerant to a condenser 52 both of which are located in a machine compartment beneath the bottom wall 24 of the cabinet.

The condenser 52 delivers liquid refrigerant through a capillary tube restrictor 54 to the inlet connection 56 of a tubular evaporator which includes a section of serpentine tubing 58 wound in serpentine fashion over the top, left side and bottom of the freezing compartment 32 after which there is a refrigerated loop 60 extending through the back Wall of the compartment 32 forwardly, beneath, and in contact with the bottom of the ice tray shelf 62 for providing for fast freezing of ice in an ice tray. The shelf 62 is beneath another shelf 64, both of which are supported upon the side wall and by a connection 66 from the top of the freezing compartment container 32. From the loop BU, the evaporator tubing extends in the form of a loop 68 upon the right side wall of the freezing container 32. The evaporator tubing then xtends in the form of a loop 10 across the back wall of the freezing` compartment container 32, after which there is another loop 12 provided on the right side wall of the freezing compartment container 32 which connects with a connection N across the back wall of the reezing compartment container 32 which ends in a trap connecting to the bottom of an accumulator or tank 15 located in contact with the upper rear edge of the freezing compartment container 32. The upper portion of the accumulator 76 is connected by the suction conduit 18 with the inlet of the compressor 53.

A thermostatic control switch 80 is provided and disclosed in diagrammatic form. It includes contacts 82 connected in series with one of the supply conductors 83 which conduct electrical energy to the motor compressor unit 50. Preferably, this switch is of the type shown in the Grooms :Patent No; 2,351,038 `and hasa temperature sensitive element in the form of a capillary tube .84 which ends ina serpentine portion 86 clamped by a clamp 88 to the right side wall of the freezing compartment container 32 in direct intimate thermal contact with the vertical portion of the refrigerant evaporator loop 68. The thermostatae is set'to close at about plus 12 F. and to .open at about minus' i F. to maintain an average temperature near ,0 F.

In prior refrigerators ,of this general type, it hasbeen customary to cool the food compartment 38 entirely by a secondary evaporating means wrapped around the walls of the liner of the 'food compartment. This resulted in very high humidity within the food compartment. This high humidity was objected to by many users. Since there was no way ,of providing a perfect seal between the interier of thefood compartment 38 and the insulation space surrounding the food compartment 38 there was a tendency for. the moisture to be carried to the coldestadjacent point. This caused moisture vapor diffusing into the insulation space to condense on the secondary evaporator tubing used for cooling the food compartment and some of this condensed moisture collected in the bottom of the insulation space.

To overcome this objectionable circumstance I provide a vertical plate-type refrigerant evaporator 90 within the food compartment 38. This is fastened by bolts and spacers 92 to the rear wall of the ,cabinet near the, upper portion thereof leaving a small space between the plate %and the rear wall of the cabinet to perrnit a column of; air to flow downwardly therebetween. The bottom of this plate 90 is connected by tubing 94 to a manually operable snap-action valve 99 mounted upon the plate, 99. The other side of the valve 99 is connected by ,a conduit 98 with the bottom of, a bent condenser m. This `condenser l2l is .clamped by a plate 122 in contact with the upper portion of ,the refrigerant evaporator loop 10 on the back wall of he freezing compartment 32. The top ofthe condenser !21 is connected .by a refrigerant conduit !23 with the .top of therefrigerated plate ,9.0 to complete the secondary refrigerant circuit which is charged with a suitable amount of refrigerant. The refrigeratedplate %is provided with serpentine refrigerant passages` 125 extending from its inlet to itsoutlet as best showninFig. 3.

The loop 10 on the back .wall of the freezing compartment 32, with which the condenser, l2l ,is

in contact, is somewhat warmer than other ;pori partment 33 suificiently low, to avoid .objection When it is d'esired .to defrostthis from users. evaporator, the defrost is readilydone by push-` ing a button provided upon the front of the valve 95. T-his will 'shut off the supply of liquid from the bottom of the condens'er !21 to the bottom of the refrigerated plate 90, thercby causing a 'slowingdown *of condensationin the condenser- 21 and a .consequent rise in .temperature of theplate.

as shown .on the portion of' the chartimarked "Sunday" which continues until the refrigerated plate 90 defrosts. After this, the button on .the front of the valve 99 is pulled out to open the valve and the refrigerated plate 90 resumes normal cycles since the circulation :of refrigerant within this secondary refrigerant circuit is re.- stored. The va'riations in 'temperature of "the refrigerated plate 90 duringnormal operation is due to the variations in temperature of theprimaryevaporator due to the cycling of the motor compressor unit under the control of the switch 80.

The bottom of the food compartment is provided with two covered pans !21 and !29 to keep food at a high humidty. These pans l21 and !29 are Conveniently arranged to pull out as drawers. Since these pans are substantially closed it is necessary to provide additional cooling so :that

the food within these pans is kept at a suitable refrigerating temperature. For this purpose there is wrapped about the sides and back of the liner for the food compartment 38 in serpentine fashion, the tubing l3l which constitutes the evaporator of another secondary refrigerant circuit *which includes the connecting conduits !33 and [35 which are connected to the bent secondary condenser [31 which is clampedialong with the condenser |2l to the loop 'o upon the rear wall of the freezing compartment container 32 by a clamping plate !39. This secondary condenser !31 condenses refrigerant at a rate to provide sufiicient evaporation of the refrigerant in the evaporator tubing l3l to keep the portion of the food compartment liner 38 adjacent the pans l21 and !29 at a temperature between about 34 and 36 F.

Moisture vapor tends to migrate to the coldest surface to which it has access. If the insulation spaces between the food compartment liner 98 and the freezing compartment ccntainer 32 within the outer shell 29 were filled with ordinary mineral or glass wool in a substantially homogeneous arrangement without any moisture vapor barriers, the moisture vaporwould all tend to collect in the form of frost or snow upon the external surface of the primary evaporator surrounding the freezing compartment container 32. The container 32 is provided with a drain (not shown) which drains into a catch pan MI directly beneath the primary evaporator 32 so that if it is desired to completely defrost the refrigerator, the frost and snow can be removed as it melts and will be caught by the catch pan [41. This catch pan MI is provided with a drain outlet [43 which extends into the food compartment 33 and is provided with a spout for discharging the defrosting water onto the vertical side wall of the food compartment liner 38.

However, to keep to a minimum the amount of frost collectinglupon this primary evaporator surrounding the freezing compartment container. I have placed the insulation such as glass or mineral wool into sealed bags of some suitable thermoplastie material such as polyethylene, or polyvinylidene chloride. such materials are substantially moisture impermeable and prevent substantially any leakage of mosture vapor into the interier of the bag containing the glass or mineral wool. These bags, such as a bag IM in the space `above the freezing compartment 32 and the bags !49' and li in the spaces at the sides .of the .freezing compartment containe: 32

:and the bag` ;l'i between., theeatch pan Mi and,

the top of the food compartment liner 38 as well as the bag !55 which fills the insulation space at the rear wall of the cabinet closely envelop the freezing compartment container 32 and the evaporator surrounding it so that the access of moisture to these cold surfaces is blocked so well that substantially no moisture can get to this surface. The material forming the bags is very exible and resilient and the glass or mineral wool used inside these bags is likewse very fiexible and resilient so that the bags hug and surround the freezng container 32 and the primary evaporator very closely, so that access to these surfaces through the insulation space is almost completely blocked.

`Since the moisture vapor is prevented from having access to the coldest surface in the refrigerator cabinet, the vapor then migrates to the next coldest surface which is the surface of the refrigerated plate es which is normally kept at a temperature varying between about l6 and 22 F. as shown by the chart in Fig. 10. From a practical standpoint it is impossible to perfectly seal the inner walls of the insulation space. Therefore no attempt is made to seal such walls and as a result breathing openings or leakage accesses occur between the interier of the food compartment liner and the insulation space to provide a path for the nigration of moisture vapor. This migration is suicient to prevent moisture from condensing on the evaporator coils 3l of the other secondary evaporator. This expedient therefore keeps the insulation space surrounding the food compartment liner 38 substantially dry. However, as an added precaution, these lower insulation spaces are likewse filled With mineral or glass wool in the sealed bags !53, !55 and 161 as described for the bags surrounding the freezing compartment container 32.

When the refrigerated plate 89 is defrosted, the water forming as a result of the melting of the frost is collected by the drip trough !59 supported by the brackets !H on the walls of the liner 38. These brackets discharge the defrost water onto the walls of the liner so that it is conducted to the bottom of the food compartment liner 38. Any Water upon the bottom of the food compartment liner 38 is conducted by a drain 15'! to a pan !55 in the machine compartment s. Here the pan [59 will be heated sufiiciently by its proximity to the motor compressor 58 into condenser 52 then the moisture will be evaporated therefrom.

This application is related to application S. N. 223,532 filed concurrently herewith.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, as may come within the scope of the claims which follow.

What is claimed is as follows:

1. Reirigerating apparatus including an insulated cabinet provided with an outer hermetically sealed shell, a box-shaped metal container within said cabinet enclosing a frozen food compartment, the walls of said container being provided with refrigerant passages, the insulation surrounding the frozen food compartment being in hermetically sealed bags in sufiiciently close contact with the freezing evaporator to substantially block the access of moisture thereto, a box-shaped metal liner within said cabinet enclosing an unfrozen food compartment, a refri erant liquefying means for supplying liquid refrigerant to and for withdrawng evaporated refrgerant from said refrigerant passages, a first secondary refrigerant circuit having an evaporating portion in direct heat exchange relation with said metal liner and having a condensing portion in heat exchange relation with said container, a second seoondary refrigerant circuit having a vertical refrigerant plate evaporatng portion located inside said liner and having a condensing portion in heat exchange relation with said container, said vertical refrigerant plate reducing the relative humidity in said food compartment.

2. Refrigerating apparatus including an insulated cabinet provided With an outer hermetically sealed shell, a box-shaped metal container within said cabinet enclosing a frozen food compartment, the walls of said container being provided with refrigerant passages, a box-shaped metal liner within said cabinet enclosing an unfrozen food compartment, a refrigerant liquefying means for supplying liquid refrigerant to and for withdrawing evaporated refrigerant from said refrigerant passages, a first secondary refrigerant circuit having an evaporating portion in direct heat exchange relation with said metal liner and having a condensing portion in heat exchange relation with said container, a second secondary refrigerant circuit having a vertical ref'igerant plate evaporating portion located inside said liner and having a condensing portion in heat exchange relation With said container, said vertical refrigerant plate reducing the relative humidity in said food compartment, a catch pan beneath said freezing compartment container extending substantially to the edges thereof, a drip pan located beneath said vertical plate evaporating portion, and liquid discharging means for said pans for discharging the liquid onto the inner surface of said liner.

3. A refrigerating apparatus comprising: a cabinet including an outer casing; a motor compressor unit and a condenser in said cabinet; a frozen food compartment in said cabinet to be maintained substantially below 32 F. Without defrosting for long periods of time, such as several months, independently of the Cycling of said motor compressor unit; an unfrozen food compartment to be maintained substantially above 32 F.; insulation inside said outer casing and outside and between said compartments with access to said unfrozen food compartment; a freezing evaporator in contact with walls of said frozen food oompa'tment; the insulation surrounding the frozen food compartment and said freezing evaporator being in hermetically sealed bags in sufficiently close contact With the freezing evaporator to substantially block the access of moisture thereto, a frosting and defrosting evaporator insid said unfrozen food compartment; a humidity maintaining evaporator surrounding the lower portion of said unfrozen food compartment; refrigerant flow and heat ex change connections between said evaporators and said motor compressor unit and condenser; a defrost water catch pan beneath the walls of said f'ozen food compartment for collecting defrost water from said freezing evaporator; and means for discharging said defrost water into said unfrozen food compartment.

4. A refrigerating apparatus comprising: a cabinet including an outer casing; a motor compressor unit and a condenser; a frozen food compartment in said cabinet to b maintained substantially below 32 F.: an unfrozen food compartment to b maintained substantially above 32` F.; insulation inside said outer casing and outside and between said compartments; a freezing evaporator in contact with wails of said frozen food compartment; the insulation surrounding the frozen food compartment and said freezing evaporator being in hermetically sealed bags in suicientiy close contact with the freezing evaporator to substantially block the access of moisture th'ereto, a frosting and defrostin evaporator inside said unfrozen food compartment; a humidity maintaining evaporator surrounding the lower portion of said unfrozen food compartment, refrigerant flow connections between said evaporators and said motor compressor unit and condenser; and a defrost water 10 catch pan beneath the walis of said frozen food compartment for collecting defrost water from said freezng evaporator; and means for discharging said defrost water from said catch pan.

EDMUND F. SCHWELLER.

References cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,798,951 Munter Mar. 31, 1931 1,952,448 Maloney Mar. 27, 1934 2,076,277 Reinhart Apr. 6, 1937 2,293,360 Reiily Aug. 18, 1942 &314.657 Norris Mar. 23, 1943 2,487,182 Richard Nov. 8, 1949 

